Charles Ellicott Commentary Proverbs 29:9

"If a wise man hath a controversy with a foolish man, Whether he be angry or laugh, there will be no rest." — Proverbs 29:9 (ASV)

Whether he rage or laugh— that is, whether the wise man treats him with sternness or good temper, yet there is no rest, the fool will not cease from his folly; or, the sense may be, “the fool rages and laughs”; he will not listen quietly to argument, by which he might be brought to wisdom, but is either violent or supercilious.